1. Field of the Invention
The present invention relates to lasers and more particularly to apparatus for measuring the performance characteristics and other aspects of laser devices.
2. Description of the Prior Art
In many laser applications, precise measurements of laser beam energy profiles are essential to predict a laser's performance in a specific application. Typically, one needs to quantify the circular symmetry and intensity smoothness of a beam energy profile to an accuracy of better than 10% of the maximum beam intensity. Pulsed laers, as opposed to continuous (CW) lasers, are more difficult to analyze although the need is no less than with continuous lasers. Pulsed lasers, used in free space communication, radar applications and elsewhere, require quantitative data on a pulse-by-pulse basis so that pulse-to-pulse variations in the beam quality can be measured. Such data is useful, for example, in predicting error rates for laser communication applications or for the predicting the accuracy of a laser radar tracking system.
Traditionally, the spatial energy distribution in a laser beam (known as the laser beam profile) has been viewed visually or with burn patterns on photo sensitive paper. Although useful for many laser applications, these qualitative observations are inadequate for those applications requiring quantitative measurements of the beam profile of pulsed lasers. Linear line scanners, such as a reticon linear CCD (Charge Coupled Device) array, or various mechanical slit scanners, have been available to measure the continuous wave beam profile along a diameter of the beam. For two-dimensional measurements these line scanners require multiple scans to obtain a two-dimensional beam profile. However, for pulsed lasers this method does not provide an energy profile from a single laser pulse.
Thus it is an object of the present invention to provide a method of obtaining energy profile measurements of pulsed lasers.
It is a further object of the present invention to utilize a video camera with a two-dimensional CCD array sensor to measure laser beam profiles in two dimensions on a pulse-by-pulse basis, thus circumventing the limitations inherent in the prior art measuring techniques.